<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>27.requestAnimationFrame</title>
</head>

<body>
  <script>
    // 16.67ms更新一次
    // 后台标签隐藏在iframe中 RAF会暂停，setTimeout依然执行
    requestAnimationFrame(function () {
      console.log(333);
    })
  </script>

</body>

</html>